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HASWELL AND WHITWORTH'S 
STEEL FORCINGS. 



BY THOS. EGLESTON, Ph.D. 



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Reprint from School oi-- Mixes Ql■Al!TERL^■. March, iS 



HASWELL AND WHITWORTH'S STEEL FORCINGS. 

BY THOS. EGLESTON, PH.D. 

Very great interest has been elicited in the making of hy- 
tlraulic forgings since it has become evident that some other way 
than hammering will have to be introduced for the treatment of 
very large steel castings either for machine or for ordnance 
purposes. 

The hammer has held such an important position in the man- 
ufacture of iron and steel for so many years that any fault found 
with it seems at first unreasonable ; yet nothing became appar- 
ent more quickly when very large pieces were required for shaft- 
ing or for ordnance purposes than that the hammer was very in- 
efficient in its action on the metal and often produced defects 
which weakened the strength of the piece. The rapid blows of light 
steam hammers often produce flaws where none existed before, 
while the blow of the heaviest hammer yet made is less efficient 
than the same force applied as pressure. One of the principal 
reasons for making forgings is to get rid of blow holes or at least 
of diminishing the size of the cavities in which the gases are con- 
tained, or which are produced by contraction, but the metal 
when brought under the hammer is often already too cold to 
make this entirely possible. 

The effort to substitute rolls for the hammer has not succeeded. 
It has be^ found that while the hammer and the rolls answered 
very well for small pieces, for very large ones they were entirely 
inadequate. One of the most striking defects in the casement 



plates made for Fort Delaware, in 1868, was, that although made 
of the very best charcoal iron, they did not stand a single fire, 
and when they were torn apart by the blow of the shot, no place 
was found larger than the palm of the hand where the welding 
was perfect. This was owing to the fact that a partial oxidation 
of the iron took place before the temperature was raised high 
enough to do the welding. On the outside such oxide can be 
easily removed by adding a flux ; on the inside this flux does 
not reach, and the oxide, if formed, remains to prevent welding. 
Often it enters the body of the piece seriously affecting its qual- 
ity, and producing effects which are rarely ever attributed to it. 
It must also, be borne in mind that the heat, which is sufficient 
for forging, is not sufficient for welding, and, also, that in large 
pieces it is quite possible that the heat may be black oh the out- 
side, while it is still high in the inside, and vice versa. The con- 
sequence is that under the ordinary circumstances of either roll- 
ing or hammering, there are both the dangers of absorption of 
oxygen and defects of welding, to contend with as well as the 
strains produced by the blow, both of which weaken the iron_ 
Besides this, small surfaces only, are acted upon at a time. With 
the hammer the shock may be too great on the outside for the 
temperature, and yet too slight to expel the cinder from the in- 
side, and at the same time the stroke may be too slight for the 
temperature of the outside to effect the welding, yet the shock 
may be sufficient, especially at the critical temperature to pro- 
duce internal strains or even serious defects. The result is that 
heavy and sudden shocks will very often break welds, indepen- 
dently of any strain which may be produced by want of proper 
annealing. It is admitted that the so-called fibrous structure of 
iron is that which makes the material the strongest ; that is a 
tendency to crystallization of such a kind that when the iron is 
submitted to a strain, the crystals are drawn out rather than sep- 
arated. The tendency towards this so-called fibrous condition 
is yery much increased by pressure and decreased by repeated 
shock. The advantage of pressure, if it can be made uniform, 
is that it works everywhere upon all parts of the iron orsteel, and 
works so slowly that the crystals have time to extend themselves 
in the direction in which the pressure acts, while with sudden and 
repeated blows this is not the case. Rolls do excellent service 
in this direction in a small way, but their action can only be on 



very small surfaces at a time, and they have been found to be 
entirely inefficient in the working of very large pieces. 

In the year 1871 Mr. J. Haswell, appreciating these incon- 
veniences of forging iron and steel, and the expense attendant 
upon the ordinary method of making pieces forged in the black- 
smith's shop very much larger than they were required, and 
then cutting them down with tools, invented a press with a 
power of 800 tons, to make the various parts of locomotives 
used by the Austrian R.R., of which he was the engineer. In the 
year 1873 he made, at the World's Fair in Vienna, a very inter- 
esting and important exhibit of the parts of locomotives that 
had been made in this way, by pressing them into cast-iron 
moulds. The pieces were made very nearly of the size required 
for the finished parts, provided they could be delivered from the 
moulds when they had been pressed into shape. When they 
could not be delivered, it was only necessary to add a small 
amount of extra material to some part which was easily re- 
moved afterwards with but little comparative waste and expense. 
It was found that the molds could be made very cheaply, and, if 
broken, could be easily replaced. The use of this press re- 
quired that there should be a certain number of forgings of each 
kind made, which he found by experiment \vas not less than 
ten for every piece, in order to make it economical. When 
more than that were required it was very cheap, the cost being 
diminished in some cases as much as 50% ; when less, it was 
too dear to be used. 

The iron brought up to red heat was placed upon the 
molds or swages, and the press brought gradually down upon 
it, so that every particle of the iron was slowly forced, without 
noise or jar, into every part of the mold, and came out with the 
so-called fibrous condition instead of being crystallized. Of 
course, the molds have to be- made so that the forgings can be 
easily delivered, which requires, in some cases, some superfluous 
thickness or extension of the parts which can be very easily 
removed. These forgings are homogeneous, have the so-called 
fibrous condition, are in such a shape that the iron is even, with- 
out annealing, in every part in the strongest possible condition. 
The work Jias grown to such an extent that several presses of two 
thousand tons are now working continuously by this method. 
The advantage of the forgings thus produced is that they are 



strong, have no tendency to crystallization, thatthey admit of being 
worked up rapidly and with the greatest economy of both time 
and labor, and of material as well. But it has always been ad- 
mitted, up to a comparatively recent period, that such forgings 
with hydraulic power could be done only upon small pieces, as the 
efforts to make large pieces had not always been successful. It 
is remarkable, the articles made by this process are almost 
always sound, and contain so few local defects that the percentage 
of loss in the forging is exceedingly small, while their quality is 
greatly increased. 

The recent demand for steel ordnance of heavy weight has 
directed attention to the many experiments made, noticeably by 
Whitworth, of Manchester, England, who, for the last twenty- 
five years, has been experimenting in this direction, and has 
succeeded in making a quality of steel which for strength and 
durability is equal to if not superior to any previously made. The 
striking peculiarity is its homogeneity, not in the sense of being 
cast from a fluid state, but in the sense of freedom from blow 
holes and of uniform composition and quality throughout. 

I had occasion, in the month of Sept., 1884, to visit the 
recently-constructed works at Manchester, which are of very 
large size and arranged with every modern convenience, both 
for making large and small tools, and to see their methods 
of measuring with the greatest accuracy very minute quantities, 
as well as of making the largest size shaftings and guns of the 
heaviest weight, all of it being done with apparently the same 
ease. Their methods of obtaining very large ingots free from 
blow holes and of forging them, are undoubtedly those which 
must be used in the near future for the treatment of steel in 
large masses. The experiments which have produced these re- 
sults were commenced in 1863, and have been continued with 
great success, but with enormous expense ever since, securing 
for the inventor the honor of knighthood, in addition to a world- 
wide reputation, not only for the size and quality, but also for 
the great accuracy of his work at the same time. 

The steel is made in the Siemens- Martins furnace, and is 
poured in at the top of steel ingot molds, which are cylindrical 
in shape and gast especially for the purpose. They are built up 
in sections, which are securely bolted together by means of 
flanges, the size and number of the sections depending on the 
length and weight of the piece to be cast. 



These molds are fitted with rods on the inside in such a 
manner as to facilitate the packing of molding sand in the 
strongest way. The melted steel is let into the ingot mold 
standing on a truck in front of the furnace. The truck runs on 
rails placed in the bottom of a trench, which is parallel to the 
furnaces, and is carried at once to the press. The head of the 
press is brought down on to the liquid steel and allowed to rest on 
it without any pressure, except its own weight, being put on it, 
and is locked in that position. The first effect is a shower of 
sparks, which, as the mold is closed by the projection on the 
head, last only a few seconds. The pressure is then very grad- 
ually applied from below. It has been found necessary to com- 
mence with the pressure as soon as the mold is closed and the 
head of the press locked, as the gases are all the more easily 
driven out of the steel as it is more fluid. The maximum 
pressure is usually arrived at in about half an hour, the time 
depending on the weight of the casting. This maximum is 
generally about 13,000 pounds to the square inch. The pres- 
sure varies with the amount of ductility required of the metal, the 
greatest being when the greatest, and the least when the least is 
required. When the process was being experimented on pres- 
sures as high as 20 tons to the square inch were used, but exper- 
ience has shown that beyond the pressure of about 6 tons, no 
sensible advantage is gained, and this is now generally adopted 
for the limits of the heaviest ingots which have as yet been 
made. 

During the time of pressure, gas in large quantities escapes 
from every aperture in the mold, which at once takes fire and 
burns on the outside. The volume of the steel diminishes in the 
course of the first five minutes as much as ^ to ^ of the length 
of the ingot. Experience has shown that there is no gain in com- 
pressing it more than this, but that the maximum pressure must 
be gradually applied, and that there is no advantage of extend- 
ing the time even for very large castings much over 35 minutes. 
After the maximum pressure has been applied it is gradually 
let down to 1500 lbs. per square inch and kept at this pressure 
until there is no longer any danger of further contraction 
of the metal, which, if allowed to act as it would without pressure, 
might crack in the interior, and thusendanger the strength of the 
ingot. The forcing out of the gases and the enormous compres- 



sion which each particle of the steel undergoes tend to make 
the ingot more homogeneous, not only preventing the forma- 
tion of cavities but closing them and welding them together while 
the steel is in a pasty condition, and probably also preventing 
to a considerable extent the liquation of the elements which 
takes place even where steel is cast in small ingots, as recent 
investigations which I have made to determine this point 
show. When the ingot has cooled and is sufficiently consoli- 
dated to be removed from the ingot mold, the pressure is re- 
moved and the ingot is taken out and reheated, unless it is hot 
enough, to be taken directly to the place where it is to be treated. 
The method is exactly the same whether a cannon of large cali- 
bre is to be made or a shafting of small diameter. The ingots 
are always cast hollow, and all the forging is done upon man- 
drils of large size. They are brought under the hammer head, 
which is pressed down a certain depth and the ingot moved 
in the swage below from its middle towards one end. At each 
successive plunge of the head, the steel yields like dough and 
moves forward towards the end, exactly in the same way. As the 
movement isslowand without shocks, all the particles move in the 
same direction. When the movement has been made from the mid- 
dle towards one end, the pieces are made to move in the other di- 
rection. It is generally found that it is best to increase the length 
of the ingot no more than six feet at a single operation. The 
ingot then goes back to the furnace, is reheated, and this oper- 
ation is continued until the requisite form is arrived at. All the 
forging being done in this way on a mandril and in a die, the 
pieces are forged with remarkable accuracy. 

The press which serves for shaping is made to accommodate 
itself to any size or form of piece*. By turning the piece round 
in the die, perfectly uniform results can be obtained as far as the 
shape of the steel is concerned, while the continued action of the 
pressure forces the steel to assume the shape which the quick, sharp 
blow of the hammer could not produce both on account of the ex- 
ceedingly short time of action, and the elasticity of the piece. The 
slow penetrating action of the press draws out the crystals and 



* In Vol. X. of the Proceedings of the U. S. Steel Institute there is a description 
of these presses. Accurate drawings have also been given of both of them in plates 
27 to 29. 



makes them assume the direction of the flow. All shocks and con- 
sequently all tendency for the crystals to assume large faces are 
avoided. The small crystals are simply forced to follow the di- 
rection which the pressure gives, and to flow continuously with- 
out changing their form or their size, their general arrangement 
only being changed, so that instead of becoming larger or more 
separated, they tend to become smaller and more closely com- 
pacted, which probably is the reason of the high quality of all 
the steel made by this process. 

The method of doing the work, and of making all the pieces 
hollow, has a decided advantage. It is well known that the 
centre of all large pieces is an element of weakness, adding 
nothing to the strength of the piece, but greatly increasing its 
weight. It is exceedingly doubtful whether by hammering, a 
large ingot can ever be made perfectly sound at the core. Many 
of the serious accidents which result from the fracture of large 
forgings have been caused by the propagation of these central 
defects to the outside, when rupture takes place. The center 
of any very large forging is always an element of uncertainty 
By removing it altogether, and forging on a mandrel, the 
pieces can be made one-third, or even more, lighter and 
stronger, thus diminishing the quantity of material while in- 
creasing its efficiency. Sir Joseph Whitworth claims that in 
addition to these advantages, the ductility of the steel is 
easily brought up 30%. All these effects become the more 
apparent according as the casting is heavier. The method 
seems to be the only one for treating very heavy castings. The 
various government commissioners, who have examined the 
method, have reported in favor of it, and some of the largest 
works in Europe are now about to adopt it, as the work done 
by the press could not be done by the hammer at all. The 
great hammers in use near St. Petersburg, at Essen and at 
Creusot, seem to have reached their limit both of size and useful- 
ness. The cost of the foundations increases so rapidly with the 
capacity of the hammer, and the danger to other structures of 
striking such heavy and quick blows as are necessary to make 
such forgings, seem to put them out of the question independ- 
ently of the effect of the blow on the quality of the steel. A 
2,000 ton press, which is entirely independent as a machine and 
produces no shocks, and requires, therefore, no expensive foun- 



dations, is equal in efficiency to an 8o-ton hammer, and can do 
as much work, and do it very much more accurately, than any 
hammer. It is doubtful whether it would ever be worth while 
under any conditions, to build a hammer that would be equal in 
efficiency to the 8 and 10,000 ton presses which are doing the 
current work of Whitworth's establishment. If we are to have 
castings capable of turning out 100-ton guns, we must have 
some other means of treating the steel than the sharp, quick 
blow of the hammer, which is quite as likely to tear and crack 
the steel in certain stages, and to produce unnecessary internal 
strains in all, as to benefit the metal. The press seems to solve 
the problem. 

I saw at the works a hollow crank shaft 58 feet long, 18 
inches in diameter, so true, when it came from the press, that 
when a sixteenth of an inch was removed from the surface the 
shaft was ready to go into its bearings. It is very doubtful 
whether so large and true a forging could have been made in 
any other way. Much larger and heavier shafts have been made, 
and have been used under circumstances where they would prob- 
ably have failed if made in any other way. One of these recently 
finished was 55 feet long, 30.5 inches in diameter, with a hole 
14 inches in diameter in its centre, and weighed 48 tons, a re- 
duction in weight of 16 tons, with much greater strength than 
the solid shaft. A tube for a iio-tgn breech loading gun was 
42.5 feet long, 27.1 inches in diameter. The centre hole was 
14.75 inches in diameter; it weighed 26 tons. If it had been 
cast solid it would have weighed 40 tons. 

Such remarkable results produced with so much certainty, have 
attracted the attention of our own government. It is doubt- 
ful, however, whether such pieces could ever be made, or such 
a work be managed by any government. It needs the stimu- 
lus of private enterprise with government patronage to make suc- 
cess possible. In the first instance private parties would probably 
be fearful of the results of a new enterprise, and capitalists with- 
out the certainty of government orders, would be slow to con- 
struct the necessary works, but it needs no gift of prophecy to 
foretell that in the near future the parts of machinery and of or- 
dnance which must be of great weight to bear very heavy 
trains, will be constructed hollow and by pressure, so as to re- 
move altogether from the piece the central part where the great- 
est uncertainty lies. 



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